I'm a Fellow at the Adam Smith Institute in London, a writer here and there on this and that and strangely, one of the global experts on the metal scandium, one of the rare earths. An odd thing to be but someone does have to be such and in this flavour of our universe I am. I have written for The Times, Daily Telegraph, Express, Independent, City AM, Wall Street Journal, Philadelphia Inquirer and online for the ASI, IEA, Social Affairs Unit, Spectator, The Guardian, The Register and Techcentralstation. I've also ghosted pieces for several UK politicians in many of the UK papers, including the Daily Sport.

Over in the New York Times Andy Revkin has a piece discussing the way that the general scientific view is that climate sensitivity is lower than many had previously assumed. This is good news of course: but one of the implications seems not to have occurred to people yet. This makes climate change itself a much cheaper problem to deal with.

Climate sensitivity is how much will the temperature change over a doubling of atmospheric CO2 (more strictly, CO2-e, taking account of methane and all the other gasses and converting them to CO2 equivalents). No, not how much it will change first and then go haywire because of all the feedbacks: how much will it change in total? There have been some pretty extreme estimates out there: up to 11 oC according to some people. Very few people and no one pays all that much attention to them, true, but they’re out there. Most of the science in this areas seems to be saying under 4.5 oC. And the estimates keep getting a little lower. As James Annan, one of the experts in the field says:

A value (slightly) under 2 is certainly looking a whole lot more plausible than anything above 4.5.

And here’s the importance of this. The lower climate sensitivity is the cheaper it is going to be to deal with it. Of course, if it’s zero then there’s no cost at all for we won’t have to do anything. But that’s more than somewhat unlikely. What a lower but still positive sensitivity does is gives us more time to deal with emissions. And the more time we have the cheaper it all becomes for two reasons.

The first is to do with the capital cycle. Say that we do indeed want to move from fossil fuels to renewables. Clearly this is cheaper if we can use our current fossil plants until they need replacing anyway. Then we build the renewables plants. The alternative, building the renewables right now and then closing down perfectly functional fossil plants of obviously more expensive. We lose that capital value of those plants we’ve closed down early. If sensitivity really was 11 oC then I’d be right there saying Dang The Cost, get them closed down now. At 3 oC, or 2 even, then we just don’t need to waste money in that manner. We’ve decades in which to make the switch over.

The second is that renewables aren’t really quite ready for prime time yet. They’re still more expensive than fossil fuels except in certain highly specific locations. That’s why we still have to subsidise them. If we’ve more time because there’s a low sensitivity then we don’t actually need to install the current generation of tee expensive renewables. We can simply wait and install the next, or the one after that, whenever it is that we get to true, unsubsidised, cost benefits. With solar this is only a few years away. With windmills I’m not entirely certain that it will ever be reached. With fuel cells I’d put it at 15 years perhaps. Low sensitivity means we’ve got the time to wait for these technologies to mature.

Another way of putting this same point is that yes, even with a low sensitivity we did need to do something to beat climate change. But a low sensitivity means we’ve already done it in large part. The billions upon billions that have been thrown at renewable technologies haven’t produced a truly price competitive technology yet. But I think that it’s entirely obvious that the next iteration or two of some of them will indeed be. At which point of course we’ll all quite naturally start using them. As those old fossil fuel plants need replacing if solar or fuel cells are cheaper then we just won’t build new fossil plants: we’ll build solar or fuel cell ones. At which point dealing with climate change costs us nothing at all.

I wouldn’t say that it is now obvious that climate change is solved: there’s still too much uncertainty about what that sensitivity is for that as yet. But the lower that sensitivity is the more it looks like we’ve already put in place the policies needed to deal with it. If we have some decades then the work that’s already being done on renewables will bear fruit and we’ll all naturally switch to them as they become cheaper than fossil fuels.

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Tim, You wouldn’t be still shooting your mouth off like this if there were real legal consequences in a real civilized society for fear mongering billions of the future’s helpless children. Climate change was a war crime.

There is no such thing as a little climate crisis outside of Harry Potter movies so how is this a crisis when not one single IPCC warning over the last two decades has ever been issued without “maybe” and “could be” and “might be”? Science has NEVER said it “WILL” happen. They only agree it’s real, but not a real crisis. A crisis that isn’t a crisis isn’t a crisis. How close to the point no return from unstoppable warming will they take us before they say a crisis is; imminent or impending or inevitable or certain or unavoidable or assured or guaranteed or “will happen” not just “might” and “could” etc. happen? The evidence for exaggeration is astounding and the world has moved on: *Occupywallstreet does not even mention CO2 in its list of demands because of the bank-funded carbon trading stock markets ruled by corporations and trustworthy politicians. *Canada killed Y2Kyoto with a freely elected climate change denying prime minister and nobody cared, especially the millions of scientists warning us of unstoppable warming (a comet hit). Meanwhile, the entire world of SCIENCE, lazy copy and paste news editors and obedient journalists, had condemned our kids to the greenhouse gas ovens of an exaggerated “crisis” and had allowed bank-funded and corporate-run “CARBON TRADING STOCK MARKETS” to trump 3rd world fresh water relief, starvation rescue and 3rd world education for just over 26 years of insane attempts at climate CONTROL.

Tim Worstall, I suspect when all is said and done decades from now they’ll conclude that climate sensitivity is even lower. Ocean heat content and satellite-era sea surface temperature data indicate the oceans warmed naturally. It’s actually pretty obvious, once you divide the oceans into logical subsets.

I’ve written dozens of blog posts about those two datasets over the past 4 years, many of which were cross posted at the most-visited website about global warming and climate change WattsUpWithThat. My most recent essay about the natural warming of the global oceans is titled “The Manmade Global Warming Challenge”, and it’s attached to the following post: http://bobtisdale.wordpress.com/2013/01/31/the-manmade-global-warming-challenge/

Sorry then to question his credentials but I still question your reliance on a single individual. Every scientific organization in the world says it is a problem and needs immediate action. Same story with 98 out of 100 experts. I don’t quote the scientist who are most alarmed (I pray it is not too late) and I don’t think you help to quote the opposite extreme. I work every day in support of a revenue neutral carbon tax; one that protects American businesses at the border, protects the most vulnerable, starts small, taxes once at the source, and allows the free market to work once CO2 pollution is not cost free.

Those that are tied to their capital are forever hoping that they can delay their investments on AGW mitigation. Unfortunately there is also evidence that climate sensitivity could also be high. To gamble that climate sensitivity is low could put our future generations at risk of a stronger warming climate.

http://www.skepticalscience.com/climate-sensitivity-tail.html

The danger with acting as though we have plenty of time to reduce our emissions is that if this turns out not to be the case, we may find ourselves beyond the point where potentially catastrophic climate change is avoidable. At the moment, the body of scientific research points to 3°C as the most likely equilibrium climate sensitivity value. It’s possible that it’s 2.5°C, or even 2°C, but there’s also evidence that it may be closer to 4°C, and it’s certainly not much below 2°C, contrary to contrarian beliefs. In any case, we need to take serious and immediate action to reduce human greenhouse gas emissions.

Fasullo and Trenberth did a study that showed high sensitivity models reproduced the cloud cover the best. This is more than likely not included in the feedback by Annan.

Again if we keep in mind we have only one chance to get it right, we are pretty much throwing our environment down the toilet. When we should be decreasing our co2 emissions, the world is increasing and possibly accelerating co2 into the atmosphere.

http://skepticalscience.com/fasullo-trenberth-2012.html

In short, while FS12 does not provide a specific measurement of climate sensitivity, it does suggest that the climate models with lower sensitivity (and ‘low’ here refers to approximately 2 to 3°C surface warming in response to doubled CO2, not the ridiculously low estimates of 1°C or less proposed by contrarians like Lindzen) are not accurately representing changes in cloud cover, and are therefore biased. Climate models with higher sensitivity – in the 3 to 4.4°C ECS range for doubled CO2 – more accurately simulate the observational RH data and thus the response of subtropical clouds to climate change.

A climate sensitivity on the higher end of the likely range obviously does not bode well for the future of the climate. As Fasullo told The Guardian, “our findings indicate that warming is likely to be on the high side of current projections.”

What it all means The exact value of climate sensitivity depends on which feedbacks you include, the climate state you start with, and what timescale you’re interested in. While the Earth has ice sheets the total climate sensitivity to CO2 is up to 8°C: 1.2°C direct warming, 1.8°C from fast feedbacks, 1°C from greenhouse gas feedbacks, and nearly 4°C from ice albedo feedbacks. The slow feedbacks have historically occurred over centuries to millennia, but could become significant this century. Including CO2 itself as a feedback would make climate sensitivity even higher, except for the weathering feedback which operates on a geologic timescale.